Fix CI failures on develop from the API performance stack (#5860)

Fixes every CI failure develop has had since the API performance stack (#5831-#5842) was merged: compiler warnings and errors (Clang, GCC 4.9/11, MSVC 2015/2017/2022), clang-tidy, cpplint, Cppcheck, IWYU, the examples check, the no-exceptions, diagnostic-positions, implicit-conversions and strict-NUL test configurations, and the MinGW link (now with LLD).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

.github/workflows/windows.yml

@@ -166,19 +166,21 @@ jobs:
       # link, but the binaries clang 11.0.1 and clang 18.1.8 then produce crash
       # before doctest prints its first line - 39 of 102 tests on clang 18.
       # Keep the objects small by splitting the test files instead.
-      # Objects with more than 65535 sections fail to link with "relocation
-      # truncated to fit: IMAGE_REL_AMD64_REL32 against `.rdata'": the MinGW
-      # linker stores the section an associative COMDAT section belongs to in
-      # 16 bits (x_associated in binutils' include/coff/internal.h), so it
-      # discards the jump tables of inline functions together with the wrong
-      # function. Each basic_json specialization a test file instantiates adds
-      # many sections, so test a second one in a file of its own.
+      # The tests link with LLD: GNU ld fails on objects with more than 32767
+      # sections with "relocation truncated to fit: IMAGE_REL_AMD64_REL32
+      # against `.rdata'", as it stores the section an associative COMDAT
+      # section belongs to in 16 bits (x_associated in binutils'
+      # include/coff/internal.h) and so discards the jump tables of inline
+      # functions together with the wrong function. Each basic_json
+      # specialization and input type a test file instantiates adds many
+      # sections, so unit-msgpack.cpp and unit-regression2.cpp kept crossing
+      # that limit as the library grew.
       - name: Run CMake
         run: cmake -S . -B build ^
              -DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" ^
              -DCMAKE_CXX_FLAGS="--target=x86_64-w64-mingw32 -stdlib=libstdc++ -pthread" ^
              -DCMAKE_CXX_FLAGS_DEBUG="-g0" ^
-             -DCMAKE_EXE_LINKER_FLAGS="-lwinpthread" ^
+             -DCMAKE_EXE_LINKER_FLAGS="-fuse-ld=lld -lwinpthread" ^
              -G"MinGW Makefiles" ^
              -DCMAKE_BUILD_TYPE=Debug ^
              -DJSON_BuildTests=On